As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
VIBRATIONS FELT IN CONTROL COLUMN & FLOOR, HEARD AT FL280 & DOWN TO 7000 FT. NO CHANGE WITHOUT AUTO PILOT OFF. REMOVED AND REPLACED THE RT AFT OUTBD ELEVATOR CONTROL CABLE IAW AMM 27-31-01 AND RT ELEVATOR TENSION REGULATOR IAW AMM 27-31-01.